Solar Energy

What is it?

Solar power is the term given for light or heat which is emitted from the sun and then harnessed by solar panels in order to generate energy which can be used for many different operations. It poses as a great alternative to fossil fuels as it is one of the cleanest energy sources known, leaving no by-products or any dangers to the environment.

How does it work?

Active energy

Passive energy

Firstly we can order the different types of solar energy into two main groups which are energy used for heating and cooling and electrical energy. In the first group there are two main techniques which are called passive solar energy and active solar energy. Passive solar energy is a way of heating and cooling the interior of a house depending on things like the orientation of walls, windows, shading and open areas. It does not require any mechanical systems. Active solar energy uses mechanical devices usually to heat water for things like pools or general home appliances. This technique uses a fluid which can transfer heat, usually a water-antifreeze mixture which stops the fluid from expanding while freezing so it can be kept at a low temperature, after being heated in the collection chamber the fluid is pumped to the storage tank where a heat exchanger transfers the heat into usable water.

Photovoltaic panel

Energy operations

The main type of energy produced in the second group is photovoltaic energy (photo meaning sunlight in, voltaic meaning energy out); this is produced using a solar panel which is comprised of many different layers such as an antireflective coating which stops the energy reflecting off the panel, an N-type silicon which has many electrons, a cell junction which allows for electron flow from the bottom P-type silicon (less electrons) to the N-type silicon (more electrons) and then out into the conducting wires. All of these operations capture light photons and push thier electrons up from the bottom silicon to the top silicon and through the conducting wires where the DC power is converted to AC power at a lower usable voltage using converters. This energy can be used in home appliances and excess energy be sold back to the grid.

 

How efficient is it, cost and energy wise?

Before making any renewable energy it can take around 5-11 years before all of the fossil fuels used making the panels is offset. At the moment most solar panels are at around 20% efficiency and some have been able to get up to around 40% but they have not been widely made as they are much more expensive and are made of more dangerous materials such as cadmium and selenium. The best panels use lithium ion batteries to store energy as less energy is lost. There have been new designs in solar panels recently this year at RMIT which are able to produce 50% efficiency by combining light and heat energy in one panel. They have an average lifespan of around 20 years.

What are the problems with it?

The total amount of the suns solar energy that falls on the earth each year is around 8500 times the energy needs of our current population. The main problem that we face in implementing solar power as a reliable energy option is finding a suitable cost efficient technology which will harness the suns energy with maximum effectiveness. If we could do this then solar power would be capable of opposing fossil fuels as the main source of electrical energy used by society. At the current time solar panels have to be continuously maintained as they are made from expensive and delicate materials such as tempered glass, this is one of the problems that solar energy poses. Most solar panels have a fairly low energy efficiency at around 20% and more costly ones are at around 30% but gathering huge amounts of panels can make up for this. In the future we may see advances in the way solar energy is harnessed as technology improves. Another problem that solar panels have is the location of where they can be placed because rainy and cloudy places don’t receive as much sunlight although in recent times new technology has been created in order to capture sunlight in these types of areas. There is a shortage in materials for some kinds of panels which drive the costs up. The storage of where energy is kept in batteries is also another problem as batteries have many issues with maintaining life. Lastly, to produce a solar panel it takes a huge amount of energy and in some cases it may take up to 11 years before the fossil fuels used to make the panels are offset with the renewable energy made from the panels.


Resources:
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http://library.thinkquest.org/20331/types/solar/problems.html, http://www.ecoworld.com/energy-fuels/how-much-solar-energy-hits-earth.html, http://www.solarhome.org/infowhatissolarpower.html, http://www.thesolarguide.com/solar-power-uses/, http://www.originenergy.com.au/2029/Photovoltaic-cells, http://www.solardev.com/SEIA-sunshinehomes.php, http://www.specmat.com/Overview%20of%20Solar%20Cells.htm, http://www.absak.com/library/solar-photovoltaic-power, http://ezinearticles.com/?How-Does-Photovoltaic-Solar-Energy-Work?&id=1020455